Astronomy current events question: Trojan asteroid characteristics, origin

Astronomy 210L, fall semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Whitney Clavin, "NASA's WISE Colors in Unknowns on Jupiter Asteroids," October 15, 2012
http://www.jpl.nasa.gov/news/news.php?release=2012-322

Observations from NASA's Wide-field Infrared Survey Explorer (WISE) space telescope of Jupiter's Trojan asteroid sizes and colors indicate that they may have:
(A) impacted Earth several times in the past.
(B) rich deposits of rare-Earth minerals.
(C) organic compounds required for life.
(D) been part of the failed formation of a dwarf planet.
(E) formed locally and then were captured by Jupiter.

Correct answer: (E)

Student responses
Sections 70178, 70186, 70200
(A) : 2 students
(B) : 5 students
(C) : 6 students
(D) : 10 students
(E) : 27 students